Replacing a drive sprocket isn't that difficult. You have to remember that they are reverse threaded so when you want to remove the sprocket you'tighten' the wrench so to speak.
If youi'd like, I can go through the way that I would remove sprockets. But that would take a while and you still wouldn't have the manual.
If you go to the Chainsaw section of TB and make a post, someone should be able to point you in the right direction.
Another source is go http://gypoclimber.com/treehouse/index.php
and look in the chainsaw forum Mangus is THE MAN for old saws.
Have you tried Google to get the manual?
Strong limbs and single ropes!
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